The present invention relates to a multi-use fan and fan motor mount assembly for use in clean air fan filter modules and workstations, clean room ceiling systems, sterile suite ceiling systems, and modular or mobile softwall clean air units.
The multi-use fan and fan motor mount assembly has an improved integral air or pre-filtered air inlet and blown air deflector in the shape of a bifurcated conical ring. The fan and fan motor are supported by motor mounts fastened to the lower outer wall portion of the conical ring. The fan and fan motor are supported substantially within the interior conical wall of the bifurcated conical air inlet and blown air deflector which results in an increase in the air pressure delivered by the fan motor mount assembly relative to existing fan motor mount assemblies. The impeller of the fan motor mount unit is mounted within the interior sides of the bifurcated conical ring such that to ⅔ to xc2xe of the fan vanes are disposed within the conical side walls.
The increase in air pressure delivered by the fan and fan motor mount assembly of this invention results in improved fan efficiency for a given final filter resistance. This increase in efficiency along with lower resistance in the fan and fan motor mount assembly results in noise abatement and energy savings.
The fan and fan motor mount assembly may be fastened directly to a subceiling of a clean room with the clean air inlet accessible to prefiltered clean air above the subceiling. A second subceiling below the fan motor mount assembly supports a series of final filters which filter the air exiting from the blown air deflector before the filtered air enters the clean room. In the event that prefiltered clean air is not available for a clean room the fan and fan motor mount assembly are fastened to a pre-filter assembly which will pre-filter the air entering into the clean air inlet of the multi-use fan motor mount assembly.
Another use of the multi-use fan and fan motor mount assembly is as part of modular or mobile softwall clean air units. In such uses the multi-use fan and fan motor mount assembly is integrally connected with a pre-filter assembly and with a final filter assembly. The final filters which are part of the final filter assembly or part or all of a clean room or sterile suite ceiling system are normally HEPA (high efficiency particulate air) or ULPA (ultra-low penetration air filters), but other types of filters having different efficiency ranges may be used in particular applications.
Another aspect of the invention is an improved air prefilter assembly. The improved air pre-filter assembly features a solid top above the air inlet to the multi-use fan and fan motor mount assembly. The solid top has at least two curved sides with apertures to receive air perpendicularly to the centerline of the air inlet of the multi-use fan and fan motor mount assembly.
The apertures or pattern of openings on the side or sides of the pre-filter assembly are covered with a prefilter to remove larger particles from the air entering the air inlet of the multi-use fan and fan motor mount assembly. The pre-filter assembly receives air through the side surface areas of the surround filter which surface areas are substantially greater than the surface area provided in existing pre-filter assemblies in which air is received through the top of a filter placed directly over the air inlet of the fan. The use of openings in the side or sides of the pre-filter of this invention provides a larger surface area in which to pre-filter air which reduces the resistance to flow of air through the pre-filter assembly into the air inlet of the fan and fan motor mount assembly.
The improved air filter assembly providing an increased air inlet surface area results in a reduction in energy necessary to draw air into the clean air fan motor mount assembly.
The disposition of the fan within the conical sidewall results in increased air pressure necessitating less fan energy to supply the final filter and associated noise abatement.
In existing clean air fan filter modules the fan is mounted primarily within the final filter assembly which compresses the air within the final filter assembly resulting in pressures above the final filter higher than necessary to pass air through the final filter. By mounting the fan and vanes substantially within the interior walls of the bifurcated conical ring the same volume of air may be supplied to the final filter assembly at a lower fan speed with less energy consumption and less noise, than in systems where the fan and vanes are located primarily in the final filter assembly. The centrifugal fan is used in conjunction with a speed control to achieve the desired air throughput through the final filter assembly. The higher deflected air pressure produced by mounting the fan and vanes substantially within the interior walls of the bifurcated conical ring also enables the fan motor mount assembly to be used in association with filters which create more back pressure than conventional final filters.
The air pre-filter assembly has been designed with side entry of incoming air to overcome two of the disadvantages of top entry pre-filters. When clean air fan filter modules are mounted in rooms where there is little space above the structure in which the clean air fan filter module is mounted, the air supply to the pre-filter assembly may be interfered with by the ceiling or structure. The use of a solid top on the pre-filter assembly of the invention combined with the larger relative surface area on the sides of the pre-filter assembly having apertures defining openings overcomes resistance to air flow found in top entry pre-filters in confined vertical spaces.
Another advantage of a side entry pre-filter is that a substantial increase of the pre-filter intake surface area may be created than is possible with an air pre-filter having the air entry to the pre-filters immediately above the air inlet to the fan motor mount assembly. In the pre-filter assembly of this invention the air pre-filter apertures and material are attached over the openings in the sides of a continuous top plate having apertures defining openings. The remaining sides and the top of the pre-filter assembly do not have apertures defining openings.
Increasing the surface area of the filter material in contact with the air decreases the static pressure through the filter material and the amount of energy necessary to pull the air through the pre-filter material.